textproduct: Albany

WHAT HAS CHANGED

Winter weather headlines and wind advisory remain in effect with no changes from the previous issuance. Otherwise, confidence continues to increase for an intense storm system bringing the potential for strong winds, heavy rainfall, and even a few thunderstorms Monday into Monday night.

KEY MESSAGES

1) There is a low to medium chance for gusty west to northwesterly reaching up to 50mph through early evening today in the Greater Capital District, western MA, Mohawk Valley, and northern/eastern Catskills to result in downed tree branches.

2) A potent storm system will bring strong winds and locally heavy rainfall tomorrow night through Monday night. Renewed minor river flooding may occur especially across NW CT.

3) Strong gusty winds expected behind this storm system Tuesday, with below normal temperatures through much of next week.

DISCUSSION

KEY MESSAGE 1...

Coming soon.

KEY MESSAGE 2... Sunday night, upper troughing becomes highly amplified over the center of the country, which will result in an expansive sfc low deepening to around 980 mb as it tracks through the Great Lakes region Monday. A southern stream impulse embedded in the SW flow out ahead of this system, along with low-level warm advection/isentropic lift will result in an area of rain tracking across the region late Sunday night into Monday morning. Some of the colder guidance indicates sfc temps may be just cold enough for some spotty freezing rain across the high terrain of the ADKs and southern Greens, but confidence is low whether or not it will be cold enough. A lull in the steady precip is expected for much of the day Monday, although there will likely still be some isolated to scattered showers around. We will be in the system's warm sector, with highs in the 50s and 60s. The southerly LLJ cranks up to 55-65 kt, so we will likely have some gusty winds again, especially in the S/SE favored areas along the western slopes of the Taconics and in the Hudson Valley.

Then, Monday evening or early Monday night, the system's cold front tracks through the region. PWATs increase to up to 1.0 to 1.2" which is 4-5 std dev above normal, and likely will be near the record daily max per the SPC sounding climatology. This anomalous moisture will overlap with very strong forcing, with strong upper divergence due to CVA and the right entrance of a jet streak to our north. Very strong low-level convergence along the front itself will further add to the forcing for ascent. Therefore, expecting a period of heavy rain with and ahead of the cold front. Total QPF amounts will likely range from around an inch to possibly 1.5-2" in the Catskills and portions of southwestern New England, so we will have to watch for potential ponding of water, river rises, and localized ice jams where any ice remains on the rivers (mainly across northern areas). There is currently a low to medium chance of minor river flooding (best chance across western New England) per the NAEFS and HEFS ensembles, so we will continue to closely monitor over the coming days. Guidance also suggests that there will be some elevated instability ahead of the front, so thunder will be possible as well. Main questions if how much (if any) surface based instability there will be. Timing for the frontal passage has trended slightly later in the evening, which looks to limit surface based instability and therefore the threat for any severe weather. However given strength of the LLJ, even modest SBCAPE values could result in a high shear/low CAPE setup with gusty winds mixing down to the surface.

KEY MESSAGE 3... Behind the front, temperatures cool quickly, so some areas may even see precip change over to wet snow briefly before ending by 12z Tuesday. It will be quite windy behind the front as well Monday night and Tuesday, with the ECMWF ensemble showing and EFI of 0.8 to 0.9 and a SoT>1, indicating fairly high confidence for strong wind gusts Monday night and Tuesday. Wind advisories will likely be needed as we get closer in time.

The airmass behind this system looks quite cold as well, with 850 mb temps dropping to -15C to possibly -20C Tuesday into Wednesday. This will result in cold/below normal temperatures both Tuesday and Wednesday. The current deterministic temperature forecast did not stray too far from the NBM for now, but will likely need to be adjusted downward in the coming days. There could also be some lake effect snow in western areas through Tuesday night, but accumulations look light. Temperatures will likely fall below freezing in most areas Tue, with gusty NW winds making it feel colder. Temperatures should moderate for the second half of next week, with generally tranquil weather expected Wednesday through Friday.

AVIATION /18Z SATURDAY THROUGH THURSDAY/

Low pressure continues to move northeast into the Canadian Maritimes this afternoon into tonight. High pressure will quickly ridge in over NY and New England tonight into tomorrow. The gusty west to northwest winds will continue prior to nightfall due to the tight sfc pressure gradient between the sfc high and departing cyclone. Cigs and vsbys will be mainly VFR with bkn-ovc cigs 3.5-5 kft AGL with brief lapses to MVFR cigs/vsbys at KPSF with snow showers. The clouds will begin to diminish between 22Z/Sat and 01Z/Sun with few- sct stratocumulus remaining and some thin cirrus. The clouds will thicken and lower overnight with mid level clouds in the 10-12 kft AGL range by 12Z/Sun for KPOU/KALB/KGFL/KPSF.

The winds will be west/northwest 12-20 KT with some gusts 30-36 KT in the early to mid pm. The winds will decrease to 8-15 KT by 00Z/Sun with some gusts 20-25 KT at KALB/KPSF. Winds become light and variable at 4 KT or less after 06Z/Sun...and will vary from the northeast to southeast at 7 KT or less after 12Z/Sun.

Outlook...

Sunday Night: High Operational Impact. Windy With Gusts To 30 kts. Definite SHRA. Monday: High Operational Impact. Windy With Gusts To 35 kts. Definite SHRA...TSRA. Monday Night: High Operational Impact. Windy With Gusts To 35 kts. Definite SHRA...SHSN. Tuesday: Moderate Operational Impact. Windy With Gusts To 37 kts. NO SIG WX. Tuesday Night: Moderate Operational Impact. Windy With Gusts To 31 kts. Slight Chance of SN. Wednesday: No Operational Impact. NO SIG WX. Wednesday Night: No Operational Impact. NO SIG WX. Thursday: No Operational Impact. NO SIG WX.

ALY WATCHES/WARNINGS/ADVISORIES

CT...None. NY...Wind Advisory until 6 PM EDT this evening for NYZ038>040- 047>054-058-063. Winter Storm Warning until 2 PM EDT this afternoon for NYZ032- 033. Winter Weather Advisory until 2 PM EDT this afternoon for NYZ042-082. MA...Wind Advisory until 6 PM EDT this evening for MAZ001-025. VT...Winter Weather Advisory until 2 PM EDT this afternoon for VTZ013-014.